1. Field of the Invention
This invention relates to medical articles, and, more particularly, relates to articles which inhibit or reduce bacterial growth and the development of thrombi in a living body during their use and to their preparation.
2. Background Art
Plastic medical articles intended for insertion into a patient must have a smooth surface to minimize patient discomfort. Another desirable feature of such articles is some means to control infection, which is a frequent complication during use of medical articles which come into contact with a body tissue or fluid. For example, infection remains a lethal complication of vascular prosthetic grafting. Catheters used for vascular access, both arterial and venous, abdominal cavity tubing, drainage bags, and various connectors are common sources of infection. In particular, a high percentage of patients who require long term urinary catheters develop chronic urinary tract infections, frequently in conjunction with episodes of fever, chills, and flank pain. Such patients are at risk of developing bacteremia or chronic pyelonephritis, conditions of high morbidity and mortality.
Medical articles are frequently fabricated from polyurethane by molding and extruding techniques. A frequent problem, particularly during extrusion, is the difficulty of obtaining homogeneous melts free of gel particles which adversely affect the smoothness of the surface of the extruded product. A discussion of these problems is given in U.S. Pat. No. 4,371,684 to Quiring et al.
Many attempts to solve the problem of infection have been directed toward adherence of an antibacterial agent to the plastic article. Gould et al., in U.S. Pat. No. 3,695,921, discloses a catheter coated with a layer of hydrophilic polymer having an antibiotic absorbed therein.
EP published application 229,862 teaches thermoplastic polyurethane medical devices having an antimicrobial agent on its surface.
Fox et al. in U.S. Pat. No. 4,581,028, teaches infection resistant plastic medical articles, such as vascular grafts, having incorporated antimicrobial agents, such as silver sulfadiazine and pipericillin. The articles are prepared by dipping procedures.
Mustacich et al., in U.S. Pat. No. 4,479,795, discloses medical devices of permeable polymers including a releasably incorporated coating of a carboxylate antimicrobial agent which diffuses to the surface of the device to form an antimicrobial barrier.
In Japanese Patent Application No. SHO-60 36064 a polyurethane or silicone catheter is dipped into an aqueous solution of chlorhexidine to absorb the chlorhexidine into the polymer. The chlorhexidine is then converted to a water insoluble form by dipping into a solution of an acid. Japanese Patent No. 59,228,856 discloses an elastomeric catheter having a water insoluble biguanide or salt thereof incorporated as a thin coating membrane in the surface of the catheter.
PCT published application No. WO 86/02561 teaches a medical device of a hydrophobic thermoplastic polymer having up to 1% chlorhexidine base coated thereon or incorporated therein.
UK Patent Application No. 2,084,466A discloses a polypropylene article rendered biocidal with chlorhexidine base, and suggests that the article may be prepared from other plastics.
Solomon et al., in U.S. Pat. No. 4,713,402, discloses a method for attachment of a quaternary salt to the surface of a polymeric article and affixation of an antibiotic or antithrombogenic agent to the salt.
In U.S. Pat. Nos. 4,521,564 and 4,642,242, Solomon et al. discloses a polyurethane article having an antithrombogenic agent covalently bonded to an amine group in the article surface.
McGary et al., in U.S. Pat. No. 4,678,660, discloses a polyurethane article having coated thereon a layer of polyurethane alloy containing a dispersed complex of a quaternary salt with either an antithrombogenic agent or an antibiotic.
Although all of the above disclosures have addressed the problems of infection and thrombogenesis during use of medical articles, satisfactory solutions have not yet been disclosed, particularly for medical articles, such as catheters, to be introduced and advanced through body passages. The present invention is directed toward providing a solution.